Disc drive data storage devices store and retrieve large amounts of computerized data in a fast and efficient manner. A typical disc drive includes one or more rigid data storage discs which are rotated by a spindle motor at a constant high speed.
Data are stored to and retrieved from tracks defined on the disc surfaces by a rotary actuator assembly (head stack assembly, HSA). The HSA supports a corresponding number of data transducing heads which are controllably moved across the disc surfaces by an actuator motor (voice coil motor, VCM).
The spindle motor and the HSA are typically mounted to a rigid base deck which cooperates with a top cover to provide a protected interior environment for the discs and heads. A flex cable assembly is used to provide the requisite electrical communication paths between the HSA and a disc drive printed circuit board (PCB) mounted to the exterior of the base deck. The disc drive PCB houses communication and control electronics for the disc drive.
The flex cable assembly includes a flex cable comprising a flexible, ribbon-like laminated member which electrically isolates and supports a number of embedded electrical conduction paths (conductors) along the length of the member.
A proximal end of the flex cable is supported by a flex cable support (flex cable clamp) mounted to the base deck, and a distal end of the flex cable is attached to the HSA. Typically, a bulkhead connector extends through the base deck to facilitate electrical connection from the flex cable support to the disc drive PCB.
The intermediary portion of the flex cable between the flex cable support and the HSA is sometimes referred to as a “dynamic loop.” The dynamic loop provides sufficient slack (strain relief) to allow the HSA to move the heads across the full radius of each disc surface.
As will be recognized, the flex cable acts as a spring and will thus provide undesired bias forces upon the HSA as the heads are moved to different positions with respect to the disc surfaces. Such bias forces tend to nominally urge the heads away from the desired position over a selected track and therefore must be within a range that can be compensated by servo control circuitry of the drive in order for the drive to operate in a reliable manner.
Disc drive designers attempt to provide flex cable assembly configurations with controllable and repeatable flex cable dynamic loop characteristics over the desired range of HSA motion. Designers further attempt to provide flex cable assembly configurations that are simple and easily installed in automated assembly processes.
With continued market driven requirements of producing higher data storage capacity drives at successively lower costs, there is a continued need in the art for improved flex cable assembly configurations. It is to such improvements that the claimed invention is directed.